Metal-oxide-semiconductor field-effect transistors (“MOSFETs”) are commonly used, alone or in combination with other transistors, as a power switching device. A MOSFET device includes a source region, a drain region, a channel region extending between the source and drain regions, and a gate structure provided adjacent to the channel region. The gate structure includes a conductive gate electrode layer disposed adjacent to and separated from the channel region by a thin dielectric layer.
When a MOSFET device is in the “on” state, a voltage is applied to the gate structure to form a conduction channel region between the source and drain regions, which allows current to flow through the device. In the “off” state, any voltage applied to the gate structure is sufficiently low so that a conduction channel does not form, and thus current flow does not occur. In the off state, the device may support a high voltage between the source region and the drain region.
Switching, or transitioning, from an off state to an on state, or from an on state to an off state, is not instantaneous. Rather, some amount of time is necessary for the voltage or current of the device to reach each state from the other, and controlling such time is difficult to achieve without extra circuit elements, known as trimming, which introduce undesirable complexity and cost into the circuit and products containing the device. Additionally, the trimming components must account for transition time dependency on temperature, topology, and even package stress. Finally, when multiple transistors are used to provide or control an output voltage or current, the voltage or current supplied undesirably fluctuates based on differentials between such times for each transistor. Among other undesirable behavior, such fluctuations cause electromagnetic compatibility (“EMC”) emissions, which increases costs (due to the need for shielding) and decreases performance.